Protective coating composition and method of preparing the same



Patented Mar. 24, 1936 PROTECTIVE COATING COMPOSITION AND METHOD OF PREPARING THE SAME Charles A. Thomas, Dayton, Ohio, assignor to Monsanto Petroleum Chemicals, Inc., Dayton, Ohio, a corporation of Delaware No Drawing.

Application May 23, 1934,

Serial No. 727,064 8 Claims. oi. 13426) This invention relates to. protective coatings such as paints, varnishes, and the like, and to driers for use in protective coating materials.

One of the principal objects of the invention is to provide a protective coating material of this character which is of good quality, highly durable, rapid drying, and which dries to a smooth film.

Another object of the invention is to provide a material for use in a protective coating containing a drying oil such as tung oil and neutral resins, which prevents the occurrence of the phenomenon known as crystallizing, during drying of such oil-resin film.

Another object of the invention is to produce a drier composition which prevents crystallization of a coating film during drying, and which accelerates the drying of such films to a degree comparable to that obtained by the use of ordinary metallic driers.

Another object of the invention is to provide a method for producing coating materials and drier compositions of this character.

Other objects and advantages of'this invention will be apparent from the following description and the appended claims.

It has long been observed by paint and varnish makers that thin films of tung oil, sometimes referred to as Chinawood oil, or of coating materials containing such oil, may on drying, produce an effect known as crystallizingfi' That is, instead of the usual smooth, glossy surface characteristic of dried paint or varnish films, the surface of the film has a crystalline structure sometimes -described as crystal rosettes. Such a crystallized surface is obviously undesirable in many types of coating material, the film being less durable and more susceptible to attack by various agencies, as well as lacking the smooth polished finish usually desired in such coatings. The cause of this phenomenon is not completely understood, although tests have shown that the effect is most pronounced when the film is dried in an oven where the atmosphere is poor in oxy-' gen, and that such a condition results where the film is dried in the presence of a burning flame.

Before use in coating materials, tung oil is usually subjected to a so-called bodying process, which comprises heating the oil to approximately 230 C. to 320 C. until the desired or consistency is obtained. Tung oil bodied in this manner, still produces a crystallized film on drying, especially under certain conditions as described above. If in bodying tung oil the heat- Ing of the oil is continued for a longer time or to a higher temperature, the oil solidifies or ,iells; so that it cannot be held at temperatures such as indicated, for any'appreciable length of time. However, when certain natural gums which are acid in character, or acid resins or 1 other acid forming compounds, are added to tung oil, jelling of the oil is retarded, and the oil can be heated at temperatures of from 230 C. to 320 C. for a period of time, for example about twenty minutes, without jelling. After such 15 treatment the oil loses the property of crystallizing on drying, and with the addition of metallic driers, will dry to form a smooth glossy film.

ing materials, such resins do not retard jelling 25 I of the oil, and the oil cannot be held at a high temperature without jelling, sufficiently long to prevent crystallization on drying of the film. The addition to the oil of any material which retards jelling of the oil, such as acid-forming compounds, is objectionable because of the tendency to darken the finished product, and to retard the drying rate as stated above, and also to make the film less durable. Certain materials 35 have been found to have the property of preventing crystallization when added to tung oil, but drying of the film appeared to be so greatly retarded as to render its use impractical.

It has been discovered that phenols and chlo- 40 phenols, such as phenol, cresol, beta-naphthol and chlor-phenol, tend to decrease or prevent crystallization of a film of tung oil, or coating .ma'terials containing tung oil.

It is known that phenols such as beta-naphthol,

.chlor-phenol, and the like, when added directly heretofore beenconsidered impractical to use such materials in coating compositions in this manner. I have found that the effect of such phenols or phenolic materials depends largely upon the type of resin used in making the coatmore marked. I have also found that with pro- Y tective coating materials of the long oil type comprising tung oil and substantially neutral resins, proportions of phenolic material such as lugs h i a that the addition beta-naphthol in excess oi 0.1% and up to 4% 5 g 3 22: i g ib z by weight, based on finished coating material; lizztion to varnfs h s i i mfilated :esfg do not retard materially the normal drying rate high acid value has a marked retarding efiect gfi gg dg r or without upon thedrying of the varnish film. With neutral me n many n 0 exposure' 10 resin varnishes, the addition of small amounts of beta-naphthol or similar phenolic inhibitors usually speeds up the drying of the film. When metallic driers and phenolic inhibitors, such as The following tables show the results of drying tests with varnishes from various resins with phenolic inhibitors of crystallization with and without driers. Other phenolic inhibitors of beta-naphthol, are both added to a varnish made crystallization may be used in the same manner 15 from a neutral resin. acceleration of drying is as beta-naphthol.

Table I.Drying time at 27 C. indirect 1ight+ Drier Drier 2 percent 4 percent Materials Blank beta-naphbeta-naph- Drier igglgfl 3 33 2 tho] I thol I m 01 thol P Hours Hours Hours Hours Hours Hours Petroleum-hydrocarbon resin (1. 1 12o 1 1. o. o. e 25 p-coumarone r I 120 120 120 l. 26 1. 0 1. o

l Percentage oi beta-ha hthol based on weight of 01]. b Based on weight oi oi lead 0.1%, manganese 0.006%. n I Gas check. 30 loo-gallon varnish. 30

Table II.Drying time at 38 C. under mercury are light 2 percent 4 percent Drier Drier 35 Materials Blank beta-naphbeta-naph- Drier f gff s a 3,22

" thol P the] F Min Minutes Minute: Minutes Minutes Minutes Petroleum-hydrocarbon resin s 30 30 25 15 15 12 4o yfiooumarone resin 4 40 40 35 20 I 20 20 40 osin ester 35 35 35 20 20 20 V I I Percentage of beta-m hthol based on weight of oil.

b Based on weight 0! ol plead 0.1%, manganese 0.005%. 0 Gas check. d loo-gallon varnish. 45

Table III.-Dryin time at 54 C. in electric oven Drier Drier -v 2 percent 4 percent Materials Blank beta-naphbeta-naph- Drier f gifg i v gg ggf 50 thol thol Minutes Minutes .Mlnulea Minutes Minutes Minutes Petrolemn-hydromrbon resin 30 30 30 8 5 5 55 umarone resin 30 30 30 8 8 10 55 can ester I 2'1 30 24 8 10 20 Percentage of bets-mi hthol based on weight of oil. Based on weighboi oi lead 0.1%, 1: 0.005%. l00-gallon varmsh. g 60 Table IV.-Drying time at 38 c. in inside sunlight Drier Drier 2 percent 4 percent 2 t 4 05 Materials Blank beta-naphbeta-naph- Drier W Perm the] the] berg1 slap): betzlxl-(nlaph- Misiuta Minutes Minutes Minute: Minutes Minutes Peholeum-hydrocarbon resin 300 210 180 10 l0 I arone resin 1 390 210 200 20 25 25 T0 .neeter 300 210 180 20 25 2 5 I Percentage of beta-ha hthol based on weight of oil.

Basedonweightoio ;leed0.1%, u 0.005%. Gas check. 4 lib-gallon varnish.

Thus when a phenolic inhibitor of crystallization is added toa tung oil coating composition containing resins of the types described, which is otherwise subject to crystallization of the film, 5 with suitable proportions of metallic driers when desired, the drying rate of the film so formed is. found to be either accelerated or not materially retarded by the addition of such phenolic materials. Thus by this invention, the danger of 10 crystallization of the film is overcome and a smooth coating film is produced, which dries at a commercially satisfactory and rapid rate.

After addition of the phenol or phenolic inhibitor, the coating composition should not be 15 subjected to a. temperature above the volatilization or subllming point of the phenol used.

Phenolic inhibitors of crystallization and metallic driers may be added separately or incorporated together in the form of a. drier composition.

20 For example, by use of a drier composition including beta-naphthol incorporated in a metallic drier, tung oil may be used in production of coating materials with any type of resin, and the film from such coating materials does not 'crystallize even under severe conditions such as described above. By use of beta-naphthol in this manner, prolonged heating of tung oil is rendered unnecessary. That is, when a drier containing beta-naphthol incorporated therein, is 30 used in a paint or varnish in the usual manner, the tung oil or other drying oil or mixture of drying oils used need be subjected only to the heat required for the simple bodying processes, and such coating materials will be entirely free from crystallization on drying of the film. The dried film is also found to be less brittle and consequently more durable than is the case when the oil has been heated for longer periods of time according to the now prevalent practice in the use of tung oil with acidic materials.

It is also found that when phenol or chlorphenol is combined with beta-naphthol and incorporated in a metallic drier and used in coating materials, such as varnishes, crystallization color of the material or film is materially lighter than when beta-naphthol alone is used. 'Consequently, for certain purposes, a mixture or composition containing beta-naphthol and a material which inhibits darkening of the film on drying,

such as phenol or chlor-phenol, incorporated in a.

metallic drier, is found desirable.

This drier composition of mixedmetallic drier and inhibitor of crystallization may be prepared 55 and shipped commercially in the dry form if desired. But before use or addition to the coating material it is first placed in solution in order to facilitate its addition to, and uniform and homogeneous distribution within, the coating 60 material. Various organic solvents which are miscible with drying oils and which are effective to dissolve .the metallic drier and the inhibitor in sufficient concentration may be used, such for example as butyl alcohol, denatured ethyl alco- 65 hol, amyl alcohol, mineral spirits, solvent naphtha, benzol, toluol, and the like. A mixture of solvents is often found desirable for this purpose, particularly when the solubility of the metallic drier or inhibitor in one solvent is notsuflicient to ive the concentration desired. A convenient method of preparation of the drier composition resides in separately dissolving the metallic drier in a solvent which is particularly suitable for this material, dissolving the inhibitor in another solvent especially suitable for such inhibitor, and

with different inhibiting materials.

of the dried film is effectively prevented, and the miscible, with the first solvent, and then mixing the two solutions.

In making a drier in accordance with this invention, any of the usual metallic driers, such as resinates, linoleates and sulphonic acid salts of naphthalene and its homologues known as soligen driers, of metals such as cobalt, lead, manganese, iron, cerium and vanadium, or mixtures of such driers, may be used. The proportion of the solvent to solid materials, that is, metallic driers and beta-naphthol, or chlorphenol, or a mixture of these, may vary widely. It has been found, however, that at least equal proportions by weight of solvent are usually required to maintain the solid constituents in solution. It has also been found that a proportion of solvent greater than three parts solvent to one part solid constituents makes the resulting solution too dilute for convenient use as a drier.

The proportion of inhibitor used in a. drier varies widely with the inhibiting material and the metallic drier used. Certain inhibiting materials are found to require a larger proportion of metallic drier to produce satisfactory drying properties in the finished varnish or coating material. The accelerating properties of metallic driers also differ, and must be taken into consideration. It is also found that the proportion of inhibitor required to effectively prevent crystallization under the most severe conditions, varies widely Thus betanaphthol, when used in combination with a drier, is found to be effective as an inhibitor in proportions of less than by weight, proportions being based on the finished varnish, and may be satisfactorily used in proportions up to 10% or drier gives complete protection from crystallization of the varnish film. and at the same time allows satisfactorily rapid drying of such film. The most desirable proportions for particular driers and solvents may readily be determined by simple test. As examples of drier compositions produced according to this invention, the following procedure and proportions have been found to give satisfactory results.

Example 1.Ten parts by weight. of beta naphthol are mixed with one part by weight of cobalt resinate. This mixture of solid constituents is then added to about twenty parts by weight of butyl alcohol, and the mixture gently heated below the boiling point of the solvent with stirring, until the solution is complete. On cooling the mixture is ready for use and may be used in the manner of a japan drier, or stored and packed for distribution. When used with varnishes up to 50 gallons in length, that is a varnish in which 50 gallons of oil is combined with 100 pounds of resin, proportions of approximately one part by weight of the drier composition produced as described above to 33 parts by weight of varnish are found satisfactory. For varnishes above 50 gallons in length, proportions of ap- .thol are mixed with one part by weight of manganese linoleate. This mixture of solid constituents is then added to about 28 parts by weight'of anhydrous denatured alcohol, and the mixture gently heated with stirring, until the solution is complete. On cooling the mixture is readyioruseandmaybeusedasindicatedin Example 1, in the manner japan drier.

Example 3. parts by weight of lead soligen drier, 1 part of manganese soligen drier and 50 .parts of beta-naphthol are mixed, together,

' This mixture of solid constituents is then added to about 75 parts by weight of anhydrous denatured alcohol, and' the mixture heated with stirring until solution is complete. On cooling the mixture is ready for use and may be used in the manner of a japan drier.

Example 4.It is sometimes desirable for convenience in bringing the materials into solution, to separately mix the metallic driers and the in.-

hibiting materials with suitable solvents for the driers and inhibitors respectively, and then combine' the resulting solutions. For example, a

- japan drier may be made by mixing the following ingredients and stirring with gentle heating until solution is complete.

Solution A Parts by weight Lead linoleate -4 18 Manganese linoleate 2 Solvent, such as turpentine or solvent naphtha- 80 The following ingredients are then mixed in the same manner, until solution is complete.

Solution B 1 Parts by weight Beta-naphthol", 3.0 Phenol 5.0 Anhydrous ethyl alcohol 2.5 Solvent naphtha 2.5

To Solution B four parts by weight of Solution A are added and mixed thoroughly.

, on cooling the mixture is ready for use, and

- may be used as indicated in Example 1, in the manner 01 a japan drier. In the'above formula, chlor-phenol may be substituted for phenol with equally good results. I

These drier compositions are used with varnishes and other coating materials in the manner described in Example 1.

In like manner, suitable proportions of phenolic inhibitors of crystallization and metallic driers may be added to the coating composition sepato be used. The above examples are merely illustrative in character, the exact'proportions required varying widely with the materials used,

' and the conditions to which the coating is to be subjected.

The coating compositions of this invention have been found particularly valuable in preparation oi varnishes and other coatings from-substantially neutral resins, such as natural neutral resins, a neutral synthetic unsaturated'hydrocarbon resin produced from petroleum hydrocarbons, and coumar'one-indene type resins, produced from solvent naphtha or other coumaroneindenecontaining materials by any of the wellknown methods.

Coatings produced according to this invention from synthetic hydrocarbon resins produced irom petroleum hydrocarbons are described and claimed in Patent No. 1,940,613 of Charles A.

Thomas,in which these coating compositions are covered generically, and 01' which this application is a. continuation in part.

Substantially neutral resins,such as the above referred-to petroleum resin, coumarone-indene resins, and the like, do not retard the drying of linseedoil, and are, therefore, particularly suitable ior use in protective coating materials. These resins, being neutral when free from impurities, do not retard the jellingoi tung oil, and when made into coating compounds containing tung oil, and used with ordinary metallic driers,' the dried film under certain conditions shows the defect above described as crystallization. However, when used with drier compositions of this,

invention no crystallization occurs, and the resulting film is found to be more durable and less brittle than with ordinary metallic driers, while the rate 01' drying is not objectionably retarded. In preparing a protective coating material such as a varnish, the drying oil such as tungoil is first bodied by heating to approximately 230 C. to 320 C. until the desired consistency or body is obtained, whichoccurs in a comparatively short time such as about five minutes, then a proportion of the substantially neutral resin, such as coumarone-indene, is added in solution in asuitable organic or hydrocarbon solvent in accordance with the practice in the varnish industry to give the amount of resin in the varnish for the particular use desired, the drier composition such as described above or the metallic drier and inhibitor are then added in suitable proportions such as.

bodiments of this invention, it is to be understood that the invention is not limited to these precise methods or precise products, and that changes may be made therein, without departing from the scope of the invention which is defined in the appended claims.

It is to be understood that the phenol may be added when dissolved or physically admixed with other materials or in loose chemical combination therewith as when dissolved in higher fatty acids or rosin, in such cases the eflicacy of the mixture is approximately equivalent'to the amount of the phenol present.

What is claimed is: v

1. A protective coating composition comprising tung oil, a coumarone-indene resin, a dried, and a phenolic inhibitor of crystallization, the tung oil being crystallizable in the composition during film drying in the absence of an inhibitor, the respec-' tung oil being crystallizable in the composition during film drying in the absence of an inhibitor form the composition being essentially free of materials that would cause excessive retardation of the rate of drying. 1

6. A protective coating composition comprising tung oil, the tung oil being crystallizable in the composition during filmdrying in the absence of I an inhibitor a substantially neutral synthetic CERTIFICATE OF EORRECTION.

Patent No. 2,055,251.

5 crystallization during dryingof the coating film coumarone-indene resin, and beta-naphthol in a 5 without retarding the drying rate of the comproportion at least approximately 1% by weight, position in film form the COmpOSitiOn being essenand less than approximately by weight, based tially free of materials that would cause excessive on the finished coating composition, the composiretardation of the rate of dry 1 tion being essentially free of materials that would 10 A Protective coating composition e p cause excessive retardation of the rate of drying. 10

- i g 11 Synthetic predlleed' from 7. A protective coating composition comprising eoumarone- Compounds. and beta-nephthel tung oil, the tung oil being crystallizable in the v in a pr p of t least approximately 1% by composition during film drying in the absence of W based on fi d coating material the an inhibitor a substantially. neutral synthetic 15 tung Oil being erystellizable in the Composition coumarone-indene resin, and phenolic inhibitor of 15 dur g fi drying in the absence 0! an inhibitor crystallization in a proportion at least approxi- A protective coating composition comprising mately 1% by weight, and less than approximately tung oil and coumarone-indene resin, such com- 10% by weight, b d n th finished coating Desitien, alone avin a tendency to crystal composition, the composition being essentially free during the d y ef the coating fi the (Beating of materials that would cause excessive retarda- 2O composition containing a suflicient proportion of ti of th t of d in a phenolic inhibitor 0f crystallization t0 substan- 8, A protective coating composition comprising tielly Prevent crystallization of t drying of the tung oil, coumarone-indene resin and a drier, said Coating fi m Without retarding the-normal rate of composition alone having a tendency to crystaldrying in the fi m the p s o being lize during the drying of the coating film, the 25 sentially free of materials that would cause excescgating composition containing a sumcient sive retardation of the ate y portion of a phenolic inhibitor of crystallization A protective coating composition comprising to substantially prevent crystallization of the film un 011 d eeumamne-indene resin, Such eompowhile atthe same time maintaining a drying rate so sition alone having a tendency to crystallize of the nun which is at least as rapid as the rate ing e d y of the coating fi the coating of drying of a film containing no inhibitoig'the Composition Containing a fiie e t p po o of composition being essentially free of materials betap to substantially Prevent y a s that would cause excessive retardation of the rate zation of the drying of the coating film without of drying.

retarding the normal rate of drying in the film CHARLES A. THOMAS, 35

I March 24, 1956.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows; Page 1 second column, line 40, for the' syllable "ch1o-" read ch1or-; page 2, line 17, in the heading to the table, before the word "indirect" insert in;page. 4, second column, line 62., claim 1, for "dried" read drier;page 5, first column, line 16, claim 5, after "inhibitor" insert the words and per'iodthe composition being essentially free of materials that would cause excessive retardation of thev rate of drying. and that, the said Letters Patent should be read 'with these 7 corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 18th day of August, A. D. 1956.

Henry Van Arsdale (Seal) I Acting Commissioner of Patents. p

tung oil being crystallizable in the composition during film drying in the absence of an inhibitor form the composition being essentially free of materials that would cause excessive retardation of the rate of drying. 1

6. A protective coating composition comprising tung oil, the tung oil being crystallizable in the composition during filmdrying in the absence of I an inhibitor a substantially neutral synthetic CERTIFICATE OF EORRECTION.

Patent No. 2,055,251.

5 crystallization during dryingof the coating film coumarone-indene resin, and beta-naphthol in a 5 without retarding the drying rate of the comproportion at least approximately 1% by weight, position in film form the COmpOSitiOn being essenand less than approximately by weight, based tially free of materials that would cause excessive on the finished coating composition, the composiretardation of the rate of dry 1 tion being essentially free of materials that would 10 A Protective coating composition e p cause excessive retardation of the rate of drying. 10

- i g 11 Synthetic predlleed' from 7. A protective coating composition comprising eoumarone- Compounds. and beta-nephthel tung oil, the tung oil being crystallizable in the v in a pr p of t least approximately 1% by composition during film drying in the absence of W based on fi d coating material the an inhibitor a substantially. neutral synthetic 15 tung Oil being erystellizable in the Composition coumarone-indene resin, and phenolic inhibitor of 15 dur g fi drying in the absence 0! an inhibitor crystallization in a proportion at least approxi- A protective coating composition comprising mately 1% by weight, and less than approximately tung oil and coumarone-indene resin, such com- 10% by weight, b d n th finished coating Desitien, alone avin a tendency to crystal composition, the composition being essentially free during the d y ef the coating fi the (Beating of materials that would cause excessive retarda- 2O composition containing a suflicient proportion of ti of th t of d in a phenolic inhibitor 0f crystallization t0 substan- 8, A protective coating composition comprising tielly Prevent crystallization of t drying of the tung oil, coumarone-indene resin and a drier, said Coating fi m Without retarding the-normal rate of composition alone having a tendency to crystaldrying in the fi m the p s o being lize during the drying of the coating film, the 25 sentially free of materials that would cause excescgating composition containing a sumcient sive retardation of the ate y portion of a phenolic inhibitor of crystallization A protective coating composition comprising to substantially prevent crystallization of the film un 011 d eeumamne-indene resin, Such eompowhile atthe same time maintaining a drying rate so sition alone having a tendency to crystallize of the nun which is at least as rapid as the rate ing e d y of the coating fi the coating of drying of a film containing no inhibitoig'the Composition Containing a fiie e t p po o of composition being essentially free of materials betap to substantially Prevent y a s that would cause excessive retardation of the rate zation of the drying of the coating film without of drying.

retarding the normal rate of drying in the film CHARLES A. THOMAS, 35

I March 24, 1956.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows; Page 1 second column, line 40, for the' syllable "ch1o-" read ch1or-; page 2, line 17, in the heading to the table, before the word "indirect" insert in;page. 4, second column, line 62., claim 1, for "dried" read drier;page 5, first column, line 16, claim 5, after "inhibitor" insert the words and per'iodthe composition being essentially free of materials that would cause excessive retardation of thev rate of drying. and that, the said Letters Patent should be read 'with these 7 corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 18th day of August, A. D. 1956.

Henry Van Arsdale (Seal) I Acting Commissioner of Patents. p 

